Facile and universal photo-induced living radical polymerization system mediated by iniferter agent and copper(ii) acetate at ambient temperature

Abstract

A facile and universal photo-induced living radical polymerization system suitable for various types of monomers, such as oil-soluble methyl methacrylate (MMA), n-butyl acrylate (n-BA) and styrene (St) as well as water-soluble poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA), was successfully developed with iniferter agent 1-cyano-1-methylethyl diethyldithiocarbamate (MANDC) and organic catalyst copper(II) acetate (Cu(OAc)₂) under UV irradiation at ambient temperature. The polymerization kinetics with different molar ratios ([MMA]₀/[MANDC]₀/[Cu(OAc)₂]₀ = 500/1/x (x = 0.1 (200 ppm), 0.01 (20 ppm), 0.0025 (5 ppm))) indicated that the novel polymerization system showed typical “living”/controlled radical polymerization features, indicated by a linear increase of molecular weights with monomer conversion while keeping relatively narrow molecular weight distributions (M_w/M_n = 1.19–1.45) for the resultant polymers. Even when the amount of Cu(OAc)₂ was minimized to only 1 ppm level, the polymerization system still showed living character. The living features of the obtained polymers were further confirmed by a successful chain-extension experiment. In addition, a possible polymerization mechanism was discussed in this work.